Aeronautical compass



K. A. KRETSCHMAR.

AERONAUTICAL COMPASS.

APPLICATION FILED APR. 8, 1920.

Patented May 23, N22

2 SHEETS-SHEET I K. A. KRETSCHMAR. AERONAUTICAL COMPASS.

APPLICATION FILED APR. 8, 1920. 3 841} D Patented May 23, 1922.

2 SHEETS-SHEET 2.

d ownhu m UNIT =4 so: a a, or remote, masses AERONAUTICAL COMPASS.

Specification of leuers mnt- P m m May 3,19 2,

4 Application filed April 8, 1920. Serial No. 372,288.

To all whom it may concern. Be it known that I, KARL A. KRE'rscH- MAR, a citizen of the United States, residing at Palmer, in the county of'Hampden and State of Massachusetts, have invented a new and useful Aeronautical Compass, of which the following is a specification.

This invention relates to a mounting for a compass for use on air-planes and airship's, although the same compass can be used in marine navigation, with or without change. Its principal objects are to provide a means of support for a compass whlch will permit of all the changes in direction of an air-ship that can possibly take place and which will at all times remain in a horizontal plane and right side up; and to provide an arrangement whereby the navigator can use the compass as a means of showing whether he is sailing horizontally or other-- wise and employ it for guiding h1s course back to a normal horizontal one.

There are times in which an air navigator is unable to tell inwhat direction he should go to sail on an even keel except by'the use of expedients, which are more or less uncertain, such as throwing articles out and watching their course in the a1r. Th1s compass, in addition to its mam ob ect, serves the purpose of enabling him always to find his true course, and find the horlzontal and vertical directions.

The invention also involves the use of improved means for supporting the compass, improved means for absorbing any. vlbration, and other improvements in details of construction as will appear. 7

Reference-is to be had to the accompanyin drawings, in which- Tig. 1 is a plan of a compass and its sup.- port constructed in accordance with this invention; I

Fig. 2 is a side ,view, partly'in section, showing it in the 'position assumed when the air ship is rising, and 4 Fig. 3 is a.transverse sectional view on the line 3-3 of Fig. 2 showing the compass frame in end elevation but at the same inclination.

The main supportis shown as comprising two end frames. They have four legs- 10 which are mounted on feet 11 with an adjusting connectionbetween them. This adjustment is shown in the simple form of a headed screw12 passing through the lower part of each leg and engaging the top of .end legs, has a projection l t each foot for holding the two parts in anydesired adjusted position. It is not absolutely essential to have each leg adjustable as one at least, can be of constant length and the others adjusted to fit it. The feet 11 are screwed down to a floor or the like.

-Each"of'the end frames, comprising two fixed with respect to the two legs and supportinga semicircular rubber bufi'er 15 which is L-shaped in cross section. This is adapted to be adusted vertically by a screw 16 and supports a ball bearing cage 17 on its upper concave surface. vAbove the :bufier 15 is a similar bufier 15. The upwardly extending part at for limiting its position'endwise with respect to these cages. This shaft carries in 1ts center, fixed to it in any desired way, a frame 22. This frame is shown as in two parts clamped to the shaft by bolts 24. At

the bottom by means 'of a pivot 25, it carries a depending weight 26 which is free to plane through the swing ina longitudinal center of the shaft.

The frame 22 has an open space 27 above I the shaft and carries above. this at its ends, two ball bearing cages 28 for the ends of a transverse shaft 29. On the shaft 29 are fixed a pair of members 30 which constitute the frame on which the compass 31 is directly carried. This is the compass frame 1 proper. These members are fixed together permit the compass itself to swing through too so that in case the machine turns over,

the compass will follow it around and its upper surface will remain in horizontal position at all times. Furthermore, it will be seen that in case the machine swings to protect it from over in the other direction and turns all the way over, the compass will also remainin horizontal position and stay at the top becausethe weight 26 will always depend toward the earth from the shaft 20. The compass frame always stays in vertical position.

It will be seen also that when the machine is tipping and the compass is therefore swinging about the shaft 29, the weight 26 is also free to swing on its pivot to keep the compass in proper position with respect to the other shaft.

rom what has been said, it will be seen that the device is universally adaptable to all positions of the machine, that the upper surface of the compass can be depended on by the operator to be always. in horizontal plane so that he can use this as a guide under all conditions of darkness and distance from the earth to guide him back to a horizontal plane and enable him to direct his machine whatever direction he desires to go. This universal adaptability of the device is an important feature because aviators have had great trouble in many instances in finding out how they are sailing and in what direction it would be necessary to go in order to return to the horizontal before trying to make the objective point, for when sailing at high speed, it is often diiiicult to be certain as to the relative position of the machine to the vertical.

Although I have illustrated and described only a single form of the invention, I am aware of the fact that many modifications can be made therein by any person skilled in the art within the scope of the invention as expressed in the claims. Therefore I do not wish to be limited to all the details herein shown and described, but what I do claim is 1. In a compass mounting, the combination of two shafts arranged at right angles "to each other, two frames, one carried by the combination of a support, a shaft carried thereby, a tilting frame on the shaft, a shaft 1 carried by said frame, a compass frame fixedly mounted on the last named shaft, and a compass fixedly secured to said compass frame above the shaft, the' compass frame being weighted below the shaft, said tilting frame being adapted to turn on an axis transverse to the axis of the other shaft.

3. in a device of the character described,

the combination of a tilting frame, a shaft carried thereby, a compass frame fixedly mounted on sa dshaft, compass fixedly secured to said compass frame above the shaft,

the compass frame being weighted below the shaft, and a second shaft, said tilting frame being adapted to turn on an axis transverse to the axis of theiirst ed shaft carried by said tilting frame a having a space below said second shaft rough which the said weight and compass can pass as the compass'frame turns.

in a device of the character described, the combination of a pair frames, a ball bearing cage carried by each frame,

yielding mea s for orting said cages yielding means for supporting said cages from their frames,.a shaft carried by saidcages, a frame fixed to saidshaft, a weight pivoted to the last named frame on a pivot below the shaft, the last named frame having bearings, a shaft in said bearings, a third frame fixed to said shaft, a compass rigidlylsecured to the third frame, and a; secon third frame below the second-shaft.

6. The combination with a mainframe tuting two separate frames, of a rubber buffer of L-shaped cross sectionIcarried by each of said frames and provided with a supporting surface, a ball bearingcage carweight rigidly connected with said having adjustable legs, the end legs consti-J ried on each of these supporting surfaces, I

said rubber also having a portion projecting behind the cage to absorb endwise shocks, a shaft rotatably carried-by said cages and compass mounted on the shaft to turn-therewith. I

In testimony. whereof I have hereunto afiixed my si nature.

ARL A. KRETSCHMAR,

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